An image-forming device using a liquid developing method such as that disclosed in Japanese unexamined patent application publication No. 2003-270986, is well-known in the art. In general, this image-forming device forms images using liquid developer having developing agent dispersed in liquid carrier. Since the image-forming device using the liquid developing method can employ a finer developing agent, the image-forming device can form images of higher resolution.
Consideration has been given to a structure for detachably (replaceably) mounting liquid developer cartridges accumulating liquid developer in the body of the image-forming device in order to facilitate the supply of liquid developer to the image-forming device. However, since the developer used in this type of image-forming device is in a liquid state, this image-forming device places a burden on the user that is nonexistent in image-forming devices employing only a developing agent (i.e., a solid developing agent).
Liquid developer is formed of a developing agent dispersed in liquid carrier, for example. Since the developing agent is primarily transferred onto the recording sheet during image formation, the amount of developing agent dispersed in the liquid carrier decreases, changing the concentration of the liquid developer. To compensate for this change in concentration, the image-forming device using a liquid developing system is provided with a configuration for adjusting the concentration of the liquid developer. Since liquid carrier is required for adjusting the concentration, a structure must be provided to supply and accumulate the liquid carrier separate from the liquid developer.
When the liquid carrier for adjusting the concentration of the liquid developer is supplied in a cartridge, this causes an operational burden on the user for replacing the liquid carrier cartridge in addition to the liquid developer cartridges, and an economical burden on the user for purchasing the liquid carrier cartridge.